Hi.

I have a 10 months old 60w redsail m500 that i had the same problem since i bought it new . I only cut 2mm acrylic and most of the time cardstock, foam so i didnt bother much. Nowdays im been cutting 4-5mm acrylic and it will take 5-6 passes at 100% power , 10mms speed. I have been adjusting/realign the mirror countless time. im pretty sure i get it pretty close to the center of the mirrors and the cut are straight. but the cutting power remains the same.